+1-800-504-5897 Help Center Check Order Status
About Us Policies Reviews How To
Free Shipping & Free Returns*

FREE SHIPPING on Over 250,000 Products

Shop now and get Free Value Shipping on most orders over $49 to the contiguous 48 states, DC, and to all U.S. Military APO/FPO/DPO addresses.

Enjoy our FREE RETURNS

We want to ensure that making a return is as easy and hassle-free as possible! If for any reason you are not satisfied with your purchase, simply return the item within 30 days of receipt, and we'll cover the cost of return shipping. Learn more about our Return Policy.

  • Entire Store
  • ...
  • Apparel & Footwear
  • Astronomy
  • Everything Else
  • Eyewear
  • Hunting Gear
  • Lab Equipment
  • Military Gear
  • Outdoor Gear
  • Photography Equipment
  • Police, EMS & Fire
  • Shooting
  • Sport Optics
  • Sports & Hobbies
TIP
Shopping Cart

Reviews & Ratings for CMMG, Inc .300 AAC Blackout Barrel Sub-Assembly — 6 reviews

(6 reviews)
CMMG, Inc .300 AAC Blackout Barrel Sub-Assembly
CMMG, Inc .300 AAC Blackout Barrel Sub-Assembly
As Low As $177.49 Save Up to 14%
View Product
Write a Review
Compare (0)
1 item has been added
Add at least two items to compare
Most Helpful Positive Review Great Barrel
I am using this in a pistol configuration. It is amazing. Using this barrel with a Yankee hill machine resonator and it functions flawlessly. Ran supersonic and subsonic ammunition without any problems.
Most Helpful Negative Review If buying for Subs, you will struggle
I purchased this barrel strictly for a 300 sub build. I know the optimal length is shorter, but I wanted to build a 16 inch sub build. Even with an adjustable gas block, I have yet to cycle rounds. It will run supers pretty well if you dial in the gas, but no luck so far with subs. Have tried a numb...
Read More...
Show
Sort by
Filter by

12.5 cmmg barrel

by MayorHaggar, Verified Owner from GA, United States Written on August 24, 2025
Fit properly and is accurate. No complaints with the product.
Would recommend: Yes
Was it helpful to you? Yes | No
Share

Thanks CMMG

by Jetster, from GA, United States Written on December 10, 2023
I am particularly fond of 12.5" battle rifles and when it comes to building them in 300 blk I always turn to CMMG and their 12.5 multi role barrel for the build.
Quality that I am confident in when it is all on the line.
Would recommend: Yes
0 of 1 found the following review helpful.
Was it helpful to you? Yes | No
Share

12.5" cmmg barrel

by Russ, Verified Owner from WI, United States Written on November 12, 2021
As expected from CMMG. No rounds down yet. Note, this is a pistol length gas system. I double checked on cmmg's website. Optics planet is wrong. I already ordered carbine length and assembled it to the gas block. :-(
Would recommend: Yes
5 of 7 found the following review helpful.
Was it helpful to you? Yes | No
Share

CMMG 16" 300 BLK Barrel

by Josh, Verified Owner from AR, United States Written on September 22, 2018
Awesome barrel that gives me the accuracy I need for my custom build. It can be difficult to find the sweet spot of accuracy vs cost when shopping for AR barrels but this one seems to have found it for me.
Would recommend: Yes
6 of 6 found the following review helpful.
Was it helpful to you? Yes | No
Share
There are no reviews that match your criteria. Would you like to review this product?